Volume and thickness change of NMC811|SiOx-graphite large-format lithium-ion cells: from pouch cell to active material level

Interplay between Elastic and Electrochemical Properties during Active Material Transitions and Aging of a Lithium‐Ion Battery

“…At high SoCs, starting at ∼4.1 V, a decline in thickness of the cell is detected. Here, the nickel‐rich NCM cathode contracts, as the c‐lattice parameter in the rhombohedral crystal structure of the layered oxide cathode declines [4,25–27] . Even though the cell is expanding during charge, the ToF decreases (Figure 1c).…”

“…A plateau in the thickness can be seen at ∼3.7 V, which can probably be associated with the graphite anode. The graphite electrode undergoes small thickness changes during the 3L‐2 stage transition that occurs around 50 % SoC [3,4,24,25] . The cathode has a thickness change that is an order of magnitude smaller in the SoC 0–80 % region [4,25,26] .…”

“…The graphite electrode undergoes small thickness changes during the 3L-2 stage transition that occurs around 50 % SoC. [3,4,24,25] The cathode has a thickness change that is an order of magnitude smaller in the SoC 0-80 % region. [4,25,26] At high SoCs, starting at ~4.1 V, a decline in thickness of the cell is detected.…”

“…[3,4,24,25] The cathode has a thickness change that is an order of magnitude smaller in the SoC 0-80 % region. [4,25,26] At high SoCs, starting at ~4.1 V, a decline in thickness of the cell is detected. Here, the nickel-rich NCM cathode contracts, as the clattice parameter in the rhombohedral crystal structure of the layered oxide cathode declines.…”

“…Here, the nickel-rich NCM cathode contracts, as the clattice parameter in the rhombohedral crystal structure of the layered oxide cathode declines. [4,[25][26][27] Even though the cell is expanding during charge, the ToF decreases (Figure 1c). This is initially counterintuitive as the cell is getting thicker and the signal needs to traverse a greater distance.…”